<?php

namespace GetId3\Module\AudioVideo;

use GetId3\Handler\BaseHandler;
use GetId3\Lib\Helper;

/////////////////////////////////////////////////////////////////
/// GetId3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.audio-video.swf.php                                  //
// module for analyzing Shockwave Flash files                  //
// dependencies: NONE                                          //
//                                                            ///
/////////////////////////////////////////////////////////////////

/**
 * module for analyzing Shockwave Flash files
 *
 * @author James Heinrich <info@getid3.org>
 *
 * @link http://getid3.sourceforge.net
 * @link http://www.getid3.org
 */
class Swf extends BaseHandler
{
    /**
     * @var bool
     */
    public $ReturnAllTagData = false;

    /**
     * @return bool
     */
    public function analyze()
    {
        $info = &$this->getid3->info;

        $info['fileformat'] = 'swf';
        $info['video']['dataformat'] = 'swf';

        // http://www.openswf.org/spec/SWFfileformat.html

        fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);

        $SWFfileData = fread($this->getid3->fp, $info['avdataend'] - $info['avdataoffset']); // 8 + 2 + 2 + max(9) bytes NOT including Frame_Size RECT data

        $info['swf']['header']['signature'] = substr($SWFfileData, 0, 3);
        switch ($info['swf']['header']['signature']) {
            case 'FWS':
                $info['swf']['header']['compressed'] = false;
                break;

            case 'CWS':
                $info['swf']['header']['compressed'] = true;
                break;

            default:
                $info['error'][] = 'Expecting "FWS" or "CWS" at offset '.$info['avdataoffset'].', found "'.Helper::PrintHexBytes($info['swf']['header']['signature']).'"';
                unset($info['swf']);
                unset($info['fileformat']);

                return false;
                break;
        }
        $info['swf']['header']['version'] = Helper::LittleEndian2Int(substr($SWFfileData, 3, 1));
        $info['swf']['header']['length'] = Helper::LittleEndian2Int(substr($SWFfileData, 4, 4));

        if ($info['swf']['header']['compressed']) {
            $SWFHead = substr($SWFfileData, 0, 8);
            $SWFfileData = substr($SWFfileData, 8);
            if ($decompressed = @gzuncompress($SWFfileData)) {
                $SWFfileData = $SWFHead.$decompressed;
            } else {
                $info['error'][] = 'Error decompressing compressed SWF data ('.strlen($SWFfileData).' bytes compressed, should be '.($info['swf']['header']['length'] - 8).' bytes uncompressed)';

                return false;
            }
        }

        $FrameSizeBitsPerValue = (ord(substr($SWFfileData, 8, 1)) & 0xF8) >> 3;
        $FrameSizeDataLength = ceil((5 + (4 * $FrameSizeBitsPerValue)) / 8);
        $FrameSizeDataString = str_pad(decbin(ord(substr($SWFfileData, 8, 1)) & 0x07), 3, '0', STR_PAD_LEFT);
        for ($i = 1; $i < $FrameSizeDataLength; ++$i) {
            $FrameSizeDataString .= str_pad(decbin(ord(substr($SWFfileData, 8 + $i, 1))), 8, '0', STR_PAD_LEFT);
        }
        list($X1, $X2, $Y1, $Y2) = explode("\n", wordwrap($FrameSizeDataString, $FrameSizeBitsPerValue, "\n", 1));
        $info['swf']['header']['frame_width'] = Helper::Bin2Dec($X2);
        $info['swf']['header']['frame_height'] = Helper::Bin2Dec($Y2);

        // http://www-lehre.informatik.uni-osnabrueck.de/~fbstark/diplom/docs/swf/Flash_Uncovered.htm
        // Next in the header is the frame rate, which is kind of weird.
        // It is supposed to be stored as a 16bit integer, but the first byte
        // (or last depending on how you look at it) is completely ignored.
        // Example: 0x000C  ->  0x0C  ->  12     So the frame rate is 12 fps.

        // Byte at (8 + $FrameSizeDataLength) is always zero and ignored
        $info['swf']['header']['frame_rate'] = Helper::LittleEndian2Int(substr($SWFfileData, 9 + $FrameSizeDataLength, 1));
        $info['swf']['header']['frame_count'] = Helper::LittleEndian2Int(substr($SWFfileData, 10 + $FrameSizeDataLength, 2));

        $info['video']['frame_rate'] = $info['swf']['header']['frame_rate'];
        $info['video']['resolution_x'] = intval(round($info['swf']['header']['frame_width']  / 20));
        $info['video']['resolution_y'] = intval(round($info['swf']['header']['frame_height'] / 20));
        $info['video']['pixel_aspect_ratio'] = (float) 1;

        if (($info['swf']['header']['frame_count'] > 0) && ($info['swf']['header']['frame_rate'] > 0)) {
            $info['playtime_seconds'] = $info['swf']['header']['frame_count'] / $info['swf']['header']['frame_rate'];
        }
//echo __LINE__.'='.number_format(microtime(true) - $start_time, 3).'<br>';

        // SWF tags

        $CurrentOffset = 12 + $FrameSizeDataLength;
        $SWFdataLength = strlen($SWFfileData);

        while ($CurrentOffset < $SWFdataLength) {
            //echo __LINE__.'='.number_format(microtime(true) - $start_time, 3).'<br>';

            $TagIDTagLength = Helper::LittleEndian2Int(substr($SWFfileData, $CurrentOffset, 2));
            $TagID = ($TagIDTagLength & 0xFFFC) >> 6;
            $TagLength = ($TagIDTagLength & 0x003F);
            $CurrentOffset += 2;
            if ($TagLength == 0x3F) {
                $TagLength = Helper::LittleEndian2Int(substr($SWFfileData, $CurrentOffset, 4));
                $CurrentOffset += 4;
            }

            unset($TagData);
            $TagData['offset'] = $CurrentOffset;
            $TagData['size'] = $TagLength;
            $TagData['id'] = $TagID;
            $TagData['data'] = substr($SWFfileData, $CurrentOffset, $TagLength);
            switch ($TagID) {
                case 0: // end of movie
                    break 2;

                case 9: // Set background color
                    //$info['swf']['tags'][] = $TagData;
                    $info['swf']['bgcolor'] = strtoupper(str_pad(dechex(Helper::BigEndian2Int($TagData['data'])), 6, '0', STR_PAD_LEFT));
                    break;

                default:
                    if ($this->ReturnAllTagData) {
                        $info['swf']['tags'][] = $TagData;
                    }
                    break;
            }

            $CurrentOffset += $TagLength;
        }

        return true;
    }
}
